Chronological Hygiene and Bayesian Modeling of Poverty Point Sites in the Lower Mississippi Valley, circa 4200 to 3200 cal BP

Developments in radiocarbon dating and analysis provide new opportunities to develop high-resolution chronologies to explore changes through time. We explore the temporality of what has been called the Poverty Point culture of the lower Mississippi Valley circa 4200 to 3200 cal BP, especially the chronology of the type site, Poverty Point. Because of its complicated material culture elaboration without evidence of agriculture, Poverty Point has been identified as the political and economic center of a complex archaeological culture. The duration of site occupation and the historical relationship between the type site and those assumed to be contemporary are critical variables for explaining the emergence of complexity at this time. Most interpretations require political or evolutionary processes that accumulate gradually over hundreds of years. Our data show, however, that there is no temporal coherence among so-called Poverty Point culture sites; among such sites, Poverty Point was occupied for a relatively short period, and it is younger than many sites thought to be derived from it. Using explicit radiometric hygiene and Bayesian analyses of dates, we reject the idea of a unified Poverty Point culture and argue instead that the Poverty Point site earthworks developed through rapid, punctuated events occurring circa 3300 to 3200 cal BP.